OK, to find out what is missing you could run:tc@box:~$ ldd $( which dosbox ) | grep 'not found'
libSDL_sound-1.0.so.1 => not found
libasound.so.2 => not found
To identify in which extensions those libraries are to be found I'd run:tc@box:~$ provides.sh libSDL_sound-1.0.so.1 ; cat info.lst
sdl-sound.tcz
tc@box:~$ provides.sh libasound.so.2 ; cat info.lst
libasound.tcz
And after loading those two extensions I'd repeat the process until no "not found" libraries show up.
As it turns out the missing dependencies are: 'sdl-sound.tcz', 'libasound.tcz', and 'libvorbis.tcz'.
Due to the fact that 'libasound.tcz' is required I'd almost put some money on the fact that 'alsa.tcz' will also be required to get any sound going. But from a "pure" dependency point of view it's not required (just that the whole lot will probably be mute without it).